freeWAIS is a text retrieval system based on the
vector space model. freeWAIS-sf is an extension of
freeWAIS, developed at the computer science department of the
University of Dortmund. sf means structured
fields and indicates the main improvement of
freeWAIS-sf. The extensions include:

improved document modeling: support for the logical
structure of documents: a document is represented as a
set of fields

introduction of different index types,
e. g. soundex and phonix for personal names or
stemming for titles

support for Boolean operators in queries

search for numeric values with special predicates
like less than and greater than.

FreeWAIS-sf is free software. It has been implemented by some
dozen developers. The resulting code is not really what one
would call aesthetic. Therefore we cannot give full guarantee
that freeWAIS-sf is full year 2000 compliant. However it's
really unlikely that you run into such a problem
unless...

... you use a version prior to freeWAIS-sf 2.0.41 and
use date indexed fields.
Within these versions the dates have been organised as
YYMMDD. In later revisions this has been changed to
YYYYMMDD.

... you depend heavily on what is written in the
documentation. The documentation is really out of date, i.
e. the change in date format described above has not been
documented.

We do not know any other parts in freeWAIS-sf where one could
get trouble from the beginning of the next century. In the
unlikely case that you run into a problem, feel free to send a
patch which fixes the problem.